PhysX on CPU or GPU?

Hello!
I've just found the option in nvidia control panel to make PhysX work on CPU or GPU. Now, I've selected CPU as my GPU is a bit weak for modern games, but now the 'tick' in GPU-Z showing PhsyX is gone. Is there any downside with this? I mean to have it on CPU rather on GPU?

 

Yes. Put it back on the GPU. Even a weak GPU is probably going to run it better than your CPU.

 

Honestly you are actually better off running it off your CPU if your GPU is weak. Running PhysX off a weak GPU will reduce your FPS significantly. On some games on a GTX 8800M I would keep GPU PhysX off because it netted me some much needed extra frames.

 

I don't know actually, I've get around 40 fps in gta iv at medium settings. Which is pretty good.

Crylo, you suggest me I should leave it on CPU?

 

Odd. I was playing mirrors edge the other day and with physx on, when i got shot at and the windows shattered, my fps dropped from 60 to 5. This was on my GTS 360m. I ended up turning it off.

 

If you are satisfied with the level of performance you are getting with PhysX running on the GPU then by all means, run it off the GPU. I personally was able to significantly improve my game experience in some cases by having it run off the CPU instead.

 

Hmmm, okay, I think I'll do some other games and see what the result is.

 

Depends on the game and whether GPU or CPU are the bottleneck. Unless you have an old or very weak CPU, I'd say run it off the CPU because most games the GPU is hardest at work.

 

I'm mainly playing gta iv, and I think my gpu actually does it worse then CPU. 9600m gt vs. T9600 x11 @ 2.93ghz.

 

I will vote for CPU. CPU is more into physics stuff, not GPU. IMHO, GPU is only for graphic-related stuff, not for calculations.

 

Well sorry to hurt your bubble, but GPU's also calculate as all the graphics we see rendered on our screens are translated by some funky math via the GPU. It is just not standard logical calculations that the GPU's are optimized on. Those things are more favored to the CPU as usual.

 

Don't worry, my bubble didn't blow up yet

Yes, ofcourse the GPU does calculations, but the CPU is much better at it. It's like asking a history teacher to say what cells are targeted by HIV ( T cells' outter "layer" - the CD-4 cells )

 

I laugh at this

But, I guess there actually is no correct answer on this.

 

My bubble is in MAXIMUM ARMOUR

Yep, you are right. Both sides have downsides : in GPU - possible frame drop; in CPU - possible bottlenecking if the CPU is already used at 80%+, but that is something I have yet to see in a game.

 

Yep. I think, as I said, do some more testing and see what gives me bewt results, in my case...

 

Let's talk some very simple benchmarks eh?

In both, my GPU running at: 610/510/1410
PhsyX running on CPU:

PhysX on GPU

Minimal diffrence, another + on GPU % when running from GPU.

 

That has to be the most useless benchmark ever. I have no idea what you are benchmarking.

 

The GPU is actually a thousand times better when it comes to some calculations, which is why I suggested leaving it on the GPU. Even a weak GPU is more powerful than a decent CPU when it comes to these things.

 

for your 9600M GT,

absolutely choose CPU. period.

 

Really? Physics are better calculated in the GPU? Why so?

 

GPU can calculate faster than CPU by parallelism.

But with a weak GPU, it should dedicate all its powers to graphics rendering. Well, not "should" but "must".

Set PhysX to GPU with a weak GPU will only slowdown the system.

 

It's debatable. The demonstrations I've seen from Intel Havok are better than anything I've seen from Nvidia PhysX. And in the demonstration, Havok said it was only using 5% of CPU. I'd rather have Physics running on only 5% of my CPU since the graphics is already taking 99% of my GPU. Also if interested, there are some great statements from John Carmack who stated simply, hardware accelerated physics from Nvidia and Aegis is stupid and a waste of hardware resource. This would include AMD's bullet physics. You have to keep in mind that both AMD and Nvidia spent so much time and money in programmable stream processors and the only sector where they have had any real impact is security systems. And those security systems are just testing network security mostly. The rest has been a failure so far. Encoding is faster and better on CPU. Rendering is not suitable for final product. Havok is still better than Bullet Physics or PhysX. Both AMD and Nvidia are doing their hardest to hype GPGPU, AMD was smart though, their APU, parallel processing will likely have real results.

First off, Physics does not take up nearly as much CPU as Nvidia claims and Nvidia fanboys. Since their comparison is with PhysX which is crippled on the CPU. Secondly, when Physics actually becames a game changer, really complex, then GPU probably won't cut it. GPU is for simple calculations, not complex. Why hasn't hardware accelerated phyics taken off? It's the same as GPGPU rendering, it's not impressive. It's just hype.

The only reason we even see PhysX is being used is because of UDK or Nvidia handing out millions. PhysX is supported natively in UDK. Notable PC PhysX games. Mass Effect 2, Bulletstorm, Mirror's Edge, Batman AA and Unreal Tournament 3. All of these are UDK games, just screams lazy, cheap. The other games that used PhysX like Metro 2033 and Mafia II were PAID BY NVIDIA... There are almost no PC game that uses PhysX because PhysX is good, I can't think of any.

I think the best physics across all games is from Valve (in general their games all have good physics comparatively to other games). Valve uses Havok. DICE uses Havok (I don't think it's debatable, destruction 2.0 in BC2 is the best physics FPS has seen so far). Blizzard uses Havok (SC2 the best physics in RTS). Diablo III will also use Havok (Likely the best physics in top down RPG action game so far). Face it, the best physics we see in games use Havok (CPU!). Mirror's Edge is the ONLY hardware accelerated Physics and that's just because it's a UDK game.

 

That was GTA IV. However, it is useless, I know that, but better then nothing, right?

This is actually what the therad is about, but it seems like people understand what in genreal is best.

Last quotes makes me only more confused

 

Funny that Valve "physics" is not real-time.

But whatever lol.

 

Okay, not to bump this therad but I'll give my results. I've have played a lot of CoD Black Ops, with PhysX on CPU. I've maxed the game out (GPU - overclocked, and out side any bulding my FPS is somewhere 10-25. But inside any bulding, my FPS is good over 40s and even seen 60s. However, I've put PhysX back on GPU, this time, out side bulding FPS was a bit better, I mean, on 20s. However, inside the buldings FPS isin't that high anymore, but actually it is more smooth overall. You don't get the HUGE diffrence when you run out on Nuketown, from 50s to 15-20 FPS it is quite noticeable. However, this is my experice about it. Just wanted to share

 

I just want to make something clear. First, this is NOT how Physx works. It is propriety by nVidia and you have to have specific software that has Physx to enable it. There are Physx games list out there and also in your nVidia control panel, an overlay to see if Physx is on. It really doesn’t matter if you have Physx set to your GPU if you don’t have any applications that don’t use it. It just won’t use a few cores to process Physx calculations. Also, your GPU will always be faster than your C2D at Physx.

 

Black Ops doesn't use PhysX... None of the COD games do.

 

Fair enough, then tell me how that makes diffrence on my FPS? I mean, I can clearly see a diffrance.

 

I don't know, but doesn't change the fact Black Ops does not use PhysX. Never has. PhysX is only used if the game supports it. Black Ops does not. None of the COD games do. Turning on GPU PhysX does absolutely nothing with Black Ops.

 

I don't get it then. I know you're talking about facts, but I'm talking about realworld performance here

 

You can talk about it all you want. PhysX has no impact on Black Ops.

 

So, how I'm getting more smooth overall performance with PhsX on GPU then?

 

Not from PhysX. Look elsewhere or you are just suffering from placebo. Saying it over and over doesn't make it so.

As someone posted before, it seems you do not know what PhysX is still.

 

Yeah, it is funny that I get diffrent levels of performance when running from CPU or GPU.

 

PhysX - Wikipedia, the free encyclopedia

note physx is coded badly so it runs slow on CPU, also no COD games use PhysX.